The fundamental processing steps for color photographic materials are a color development step and a desilvering step. In the color development step, light-exposed silver halides are reduced by a color developing agent to form silver and the oxidized color developing agent reacts with color formers (couplers) to provide dye images. In the subsequent desilvering step, silver formed in the color development step is oxidized by the action of an oxidizing agent (called as bleaching agent) and then dissolved by a complexing agent for silver ion called as a fixing agent. By the desilvering step, solely dye images are formed in the color photographic material.
The above-described desilvering step is usually performed by two baths, i.e., a bleach bath containing a bleaching agent and a fix bath containing a fixing agent or by one bath, i.e., a blix bath containing a bleching agent and a fixing agent together.
In general, as the bleaching agent, ferricyanides, dichromates, ferric chloride, aminopolycarboxylic acid metal complex salts, and persulfates were used but recently aminopolycarboxylic acid metal complex salts have been used from the problems of toxicity and safety.
However, aminopolycarboxylic acid metal complex salts have the problems that the oxidative power thereof is weak, whereby the bleaching speed of developed silver is slow, and also the density of cyan dye images formed in a color developer solution is reduced (fluctuated).
For solving these problems, there is provided a method of adding a bleach accelerator to a bleach bath, a blix bath, or a pre-bath thereof as described, for example, in U.S. Pat. No. 3,893,858, Japanese Patent Application (OPI) Nos. 95630/77, 26506/80, 42349/74, 52534/79, 5630/74, Japanese Patent Publication Nos. 8506/70, 2586/74, etc. (The term "OPI" as used herein means an "unexamined published patent application). However, in the above method, a satisfactory bleach accelerating effect is not always obtained or sparingly soluble precipitates are formed with the increase of the amount of the processed color photographic materials.
Thus, a method of accelerating the bleaching by adding a compound similar to the compounds represented by formula (I) described hereinafter, which are used in this invention, to color photographic light-sensitive materials or the processing solution is proposed in U.S. Pat. No. 4,552,834 but the patent does not disclose a combination of the compound and a cyan coupler as in the present invention.
Also, as a method for accelerating a bleach and/or a blix, processing color photographic materials at such a low pH as an aminopolycarboxylic acid metal complex salt strongly functions its oxidative power has been performed, but in their method, there are problems in that a cyan dye density is liable to lower and also a thiosulfate or a sulfite existing in the processing solution is decomposed fast to make the performance of the processing solution unstable.
On the other hand, the increase of the pH of the bleaching or blixing solution encounters the problems that the desilvering property is reduced and also the formation of color fog at unexposed portions is increased.
For eliminating these disadvantages, phenolic cyan couplers having a phenylureido group at the 2-position and a carbonamido group at the 5-position, which is reluctant to reduce the cyan image density in the case of processing with a bleach solution or a blix solution having a weak oxidative power or a bleach solution or a blix solution having low pH are proposed in Japanese Patent Application (OPI) Nos. 65134/81, 204543/82, 204544/82, 204545/82, 33249/83, 33250/83, etc. However, even when these cyan couplers are used, a thiosulfate or a sulfite co-existing in a bleach solution or a blix solution is decomposed at a low pH range to make the performance of the cyan couplers unstable and the desilvering speed can not be said to be satisfacturily.
For further improving the above-described techniques, a method of processing a color photographic light-sensitive material containing the cyan coupler, which is used in the present invention, with a blix solution containing a diethylenetriaminepentaacetic acid iron (III) complex salt and having a pH of at least 4.0 is proposed in Japanese Patent Application (OPI) No. 151154/84 but the effect is obtained only in the case of using a blix solution containing a limited bleaching agent and also the effect is small.
Accordingly, the developments of a color photographic light-sensitive material which shows a high desilvering speed (bleaching or blixing speed), can be stably processed, does not result in fluctuations of the cyan image density by processing, and has high fastness and also a processing system for the color photographic material, have been keenly desired.
Also, since the requirement for a high image quality of a silver halide color photographic material has recently become more and more severe and, in particular, the decrease of picture size of a photographic light-sensitive material with the decrease of the size of cameras has been desired, the requirement for the development of the technique about the improvement of image quality (in particular, graininess) in a color photographic light-sensitive material has become very strong.
As the techniques for improving the graininess of color photographic materials, a method of increasing the utilization effect of incident light in the color photographic materials by using core/shell type silver halide emulsion grains of a two-layer composed of a core portion having a high silver iodide content in the inside of the emulsion grain and a shell portion having a low silver iodide content to separately provide the functions from the light receiving to the image formation as well as possible as described, for example, in Japanese Patent Application (OPI) Nos. 153428/77, 138538/85, 143331/85, and Journal of Imaging Science, Vol. 29, No. 5, page 193 is useful.
On the other hand, recently, with the increase of the employment of so-called mini-laboratory, the requirement for simplicity and quicker processing of color photographic materials and the lowering of the cost for processing has become severe and the simplification of processing steps, the shortening of processing time, and the reduction of the amount of processing chemicals have become inevitably required.
In particular, when a color photographic light-sensitive material containing a silver halide emulsion having a phase of high silver iodide content as the two-layer structure silver halide grains as described above is processed, the bleaching speed is liable to be delayed, and hence there is a serious problem that the desilvering becomes poor.
By the reasons described above, the desilvering technique for the color photographic materials using a silver halide emulsion having a phase of high silver iodide content has not yet been established at present and also the improvement for the desilvering processing of color photographic materials containing a silver halide emulsion having a phase of high silver iodide content has not yet been developed.
Still further, for obtaining good color image quality in the case of forming color photographic images, it is important that the change in finish property of the development in the case of processing color photographic materials is less. For realizing the aforesaid matter, it is effective that the formation of fog in the case of processing color photographic materials is less and also the change in fog during the storage of color photographic materials is less. Since in the case of processing color photographic materials giving high fog, the difference in fog between the case of developing under the development condition of liable to forming fog by the increase of the temperature of the developer solution or the increase of the pH thereof and the case of developing under the development condition of being resistant to the formation of fog by the decrease of the temperature or the pH of the developer solution is liable to become larger, the fluctuation of the development finish property is liable to become larger as the result, thereof. Also, as a matter of course, color photographic materials giving large change of fog when stored in the undeveloped state are liable to cause the fluctuations in the development finish property.
As one of means for solvent the problems of preventing the occurrence of fog of such silver halide color photographic materials and of preventing the increase of fog formation by storing the color photographic materials in the undeveloped state, it is known to incorporate various antifoggants into color photographic materials.
That is, it is known that heterocyclic mercapto compounds such as mercaptothiazoles, mercaptobenzthiazoles, mercaptobenzimidazoles, mercaptothiadiazoles, mercaptotetrazoles (in particular, 1-phenyl-5-mercaptotetrazole), mercaptopyrimidines, etc., have a remarkable effect for the prevention of the formation of fog and also for the prevention of the increase of fog when color photographic materials are stored in the undeveloped state.
In particular, it is described in Japanese Patent Publication No. 9939/83 that the inhibition of the formation of fog at color photographic processing of color photographic materials and the prevention of the increase of fog at the storage of color photographic materials under the undeveloped state can be realized without reducing the sensitivity of the color photographic materials by the use of a compound similar to the compounds represented by formula (III) described hereinafter, which are used in the present invention. However, there are no descriptions in the aforesaid patent about the influences of the compound similar to the compounds represented by formula (III) in this invention on the bleach or blix processing, the effect of incorporating the compound similar to the compounds of formula (III) in color photographic materials together with the compound represented by formula (I) and/or the compound represented by formula (II) in this invention, which is described hereinafter, and the effect of the case of color photographic processing color photographic materials containing the compound similar to the compounds of formula (III) in the existence of the compound represented by formula (I) and/or the compounds represented by formula (II) in this invention.
Also, in British Patent No. 1,138,842, Japanese Patent Publication Nos. 4980/85, 6506/85, 6508/85, 16616/85, Japanese Patent Application (OPI) Nos. 61749/85, 95540/85, and 125843/85, it is described that by adding a compound having a mercapto group to a bleach bath, a blix bath or a pre-bath therefor, a bleach accelerating effect is obtained. However, since, for example, the compounds disclosed in Japanese Patent Publication No. 6506/85 described above do not have a substituent such as --COOH, --SO.sub.3 H, --NR.sup.2 R.sup.2, etc., while the compounds disclosed in Japanese Patent Publication No. 6508/85 have --COOH as the substituent, it is very difficult to estimate the bleach accelerating effect from the chemical structure of a compound for use.
Furthermore, the above-described patents and patent applications all describe the effect only in the case of incorporating the compound having a mercapto group in processing solution and there are no descriptions therein about preferred chemical structures of the compounds incorporated in color photographic materials.
Japanese Patent Application (OPI) No. 127038/84 discloses that a color photographic material containing a mercapto compound having an amino group and 1-phenyl-5-mercaptotetrazole having an amido group as a combination thereof is excellent in storability and shows an improved bleaching property, but the invention described therein relates to a color photographic processing using a persulfate as a bleaching agent. However, since a persulfate has a weaker oxidative power than an aminopolycarboxylic acid metal salt and shows a slow desilvering speed for developed silver, it is difficult to anticipate whether or not the combination disclosed in the aforesaid patent application is also effective in a color photographic processing using an aminopolycarboxylic acid metal salt as a bleaching agent. Moreover, when a persulfate is precipitated from the processing solution, there is a possibility of causing explosion.
Accordingly, means for improving the bleaching property in a color photographic processing process using a safe aminopolycarboxylic acid metal salt as a bleaching agent have been strongly desired.
Also, Japanese Patent Application (OPI) No. 168049/83 describes that a color photographic material containing a compound having a partial structure of ##STR3## and 1-phenyl-5-mercaptotetrazole as a combination thereof shows less change of performance when the color photographic material is stored for a long period of time and shows an imProved bleaching property in the color photographic processing using an aminopolycarboxylic acid metal salt as a bleaching agent. However, the effect is still unsatisfactory.
Accordingly, from these circumstances, the developments of color photographic materials having safer shelf life and a color photographic system having improved bleaching property have been strongly desired.
In this respect, a method of accelerating bleaching by adding a compound similar to the compounds represented by formula (I) in the present invention is proposed in U.S. Pat. No. 4,552,834 but this patent does not disclose a combination of the compound with a mercapto compound as well as does not teach a method of both accelerating the bleaching and reducing the change of the performance by the storage for a long period of time.
Also, a method of accelerating the bleaching by adding a compound similar to the compounds represented by formula (II) described hereinafter, which are used in the present invention, to the processing solution is proposed in Japanese Patent Application (OPI) No. 95630/78, but a combination of the compound and a mercapto compound is not disclosed in the patent application.